One person is in critical condition and another has moderate injuries following a serious crash in the Bay of Plenty Police district.

A police spokesperson says a stwo-vehicle crash is blocking the intersection of State Highway 5 and Harwoods Road (SH28) at Tapapa, north of Putaruru, is blocked and people should avoid the area.

The crash happened about 6.05am.

"One person is reported to have critical injuries, while another is in a moderate condition.

"Diversions are being put in place and the Serious Crash Unit will be investigating.

"Motorists should expect delays."