People heading out on the water with commercial operators to see the Prada Cup yacht racing are being told to look for the flag.

Maritime NZ has distributed more than 110 distinctive yellow and pink flags to approved commercial operators providing on-the-water viewing for the racing starting this week.

The presence of the flag means spectators can have confidence they are travelling with an approved commercial operator as they watch the America's Cup yachts.

'The flag shows that the operator is in a Maritime NZ recognised safety system or has an exemption,” says Maritime NZ's compliance manager – North Neil Rowarth.

Exemptions are only granted when operators can show they have an equivalent or better level of safety, he says.

'Commercial operators are regularly audited to make sure the way they work is safe.

'Crews must be appropriately trained and certified and the vessels must be surveyed.”

For these reasons, Neil recommends that people look for the pink and yellow flag if they're planning on paying to go watch the racing.

He warns against recreational boaties planning to make money by charging to take people out because maritime officers will be around during the racing.

'If you are using a recreational boat to take out fare paying passengers then you are breaking the law and there will be consequences.

'You also may not be covered by your insurance policy – this could be very expensive should something go wrong. It is simply not a good idea to be doing it,” says Neil.