Tui billboards referring to Winston Peters don't breach electoral law, the Electoral Commission has decided.

The billboards, which went up in August, say: "When Winston says no, he means no -- Yeah right".

They refer to Mr Peters holding up a `No' sign in February when he was asked if he or New Zealand First had ever received a donation from expatriate billionaire Owen Glenn.

Mr Peters admitted in July that Mr Glenn contributed $100,000 in 2006 to his legal expenses.

The commission had to decide whether the billboards were election advertising, in which case they would have been out of order.

It said tonight it had decided they were not election advertising within the meaning of the Electoral Finance Act.

In other determinations, the commission said ACT failed to disclose donations of office space in 2005 and had to file amended returns, and New Zealand First's secretary had not committed an offence in relation to the party's 2007 donation return.