The Canada Pension Plan Investment Board (CPPIB) moves to buy Sydney-based infrastructure group Intoll.

CPPIB bid provides three options for Intoll shareholders including a cash offer equivalent of $1.53 per Intoll stapled security.

The offer represents a significant premium to Intoll's recent trading price, according to CPPIB.

While CPPIB is doing due diligence on the firm, there's no guarantee the pension fund will outline a formal binding proposal to buy Intoll's stapled securities, according to a company statement.

"The directors of Intoll have not formed a view as to the adequacy of the proposal and accordingly recommend that Intoll security holders take no action at this time," said Paul McClintock, chair at Intoll.

Intoll's portfolio includes a 30 per cent stake in the 407 ETR in Toronto, Canada and a 25 per cent interest in the Westlink M7 in Sydney, Australia.

The firm's share price rose more than 30 per cent to $1.45 per share after the announcement. Intoll hired UBS as its financial adviser and Mallesons Stephen Jaques as its legal adviser for the process.

Richard Elmslie, investor director and senior portfolio manager at infrastructure fund manager RARE Infrastructure, an Intoll shareholder, said the bid is reasonable.

"We bought in at around $1.06 [six months ago] so at $1.50 per share, it looks reasonably valued … we'll just have to wait on the due diligence from CPPIB," he said.

Intoll's share price was $1.44 per share following today's morning trading period.

In November, CPPIB and another pension fund bid for Transurban, which was rejected by the company.