His way was cleared yesterday after he increased his offer for SIG, leading European-based Ferd Holding and CVC Capital Partners to end their joint bid for the company.
Hart wants to merge other holdings in his investment company, Rank Group, together with SIG, to make it the world's second largest producer of beverage packaging after Sweden-based Tetra Laval.
For processors SIG will make up part of a larger supplier, giving the company more leverage over setting prices for its packaging.
On the positive side, the move could also provide more healthy competition in the market against Tetra's dominance.
Tetra Laval subsidiary Tetra Pak has an 80 per cent share of the carton packaging market, according to a Bloomberg report.
The group is owned by Sweden's Rausing family.
SIG is the world's second-biggest maker of drink cartons, with a 15 per cent share of the market.
Hart's Rank Group yesterday said it now holds 22 per cent of SIG and increased its offer price to CHF435 per share in cash.
His latest offer valued the company at about €2.5bn.
SIG will announce its position on Rank Group's latest offer by 22 March, the company said.
Hart's takeover bid for SIG was strengthened after Ferd and CVC said they would not raise their offer and announced they would sell all their remaining shares in SIG.
The companies had been jointly bidding for SIG since September, countering previous offers for the company made by Hart.
The two companies said they will divest their current 2.38 per cent remaining stake in SIG.
Shares amounting to 8.24 per cent of SIG's total share capital have already been sold, the two companies said.
Ferd is the parent of Norway-based Elopak.
London-based CVC Capital Partners is an investment holding company.
Elopak has about 7.5 per cent of the market, with International Paper ranking fourth, according to Bloomberg news.
SIG put itself up for sale through a public auction last year offering competitors a chance to put together a beverage carton packaging company to rival the dominance of Tetra Laval.
SIG had sales of €1.2bn last year from products such as cartons for long life drinks and polyethylene terephthalate (PET) bottles.
The SIG purchase would add to Rank's considerable holdings in the global packaging industry, a portfolio that Hart's investment company has been building for the past year.
Earlier this year Hart bought Carter Holt Harvey, the New Zealand forestry and packaging group for NZ$3.3bn (€1.7bn).
Hart has since sold the company's forestry unit to US-based Hancock Group for about NZ$1.5bn (€792m).
Earlier this CHH's packaging operations.
In December he also agreed to purchase International Paper's drinks packaging business for NZ$725m (€382.8m).
Ferd and CVC's decision to drop out of the bidding war for SIG may have been influenced by the European Commission's decision on 22 December to open an investigation into whether their combination with the company would diminish competition in the market.
Both Elopak and SIG are suppliers of carton filling machines and carton material for non-carbonated liquid food products packaging.
Under EU rules the Commission had 90 working days, until 15 May, to take a final decision on whether the concentration would significantly impede competition.
The carton packaging market in the EU is characterised by a rather exceptional concentrated market structure with Tetra Pak dominating the market, while SIG and Elopak compete fir the rest of the business, the Commission noted.
Therefore the proposed transaction would combine the second and the third largest suppliers, while Tetra Pak would remain the largest competitor.
The Commission also said that the structure after such a merger would mirror that of the upstream market for liquid packaging board, the main raw material used to produce carton packaging material, which has existed since the acquisition of AD Cartonboard by Korsnäs in May last year.
"The relevant product and geographic markets have been investigated in a number of previous merger and antitrust decisions involving the market leader Tetra Pak," the Commission stated. "
The parties' activities overlap in the market for high-acid aseptic liquid products (juices) where Elopak is a recent entrant.
In its detailed investigation, the Commission will scrutinise how the removal of Elopak as competitor would affect the competitive dynamics in these markets."
In the statement yesterday the two companies continued to argue that their offer would have made the best combination of forces: "Ferd/CVC continue to be convinced that combining SIG with Elopak would have offered SIG and its stakeholders the best industrial prospects," the two companies said.
"However, Ferd/CVC are not willing to pay a price for SIG that could compromise the business rationale of the transaction....with a new owner of SIG becoming apparent, Ferd/CVC wish all employees of SIG good luck."