Biosecurity vehicle inspector Jevic NZ has raised its bid for Vehicle Inspection New Zealand Limited (Vinz) by 30 per cent.

Jevic has revised its offer to $2.15 per share, up from $1.65, after weighing up an independent advisor's report.

Vinz' s board has unanimously recommended the new offer to shareholders and its five directors have agreed to sell their collective 9.5 per cent stake, Jevic said in a statement.

The new bid values Vinz at $5.37 million and is 43 per cent higher than the price its shares was trading at before the announcement at $1.50. Previously Jevic had received acceptances for just under 25 per cent of Vinz' shares.

Jevic chief executive Euan Philpot said his company raised its offer after considering the more-detailed information the independent adviser had access to.

"These included 2012 management accounts, 2013 budgets, and forecasts for 2013, 2014 and 2015," Philpot said.

"After considering the evidence and analysis in his report we reached the view that an increase was warranted."

The $2.15 offer sits between two of the independent advisor's three valuation ranges, one of which was $1.77-$1.93 and the other for $2.27-$2.55 per share.

A well-known source of vehicle warrants of fitness, VINZ also completes entry certification for the New Zealand Transport Agency on about 40 per cent of vehicles entering the country.

Its shares are traded on the Unlisted platform.

Jevic's offer closes on February 13 and is conditional on receiving more than 50 per cent of shares.

- © Fairfax NZ News