Official conservation agencies in China and New Zealand on Friday agreed to work together to protect wetlands used as nesting areas on epic bird migrations.

The wetlands are visited by red knots and bar-tailed godwits during their 12,000-kilometer migratory flights.

A memorandum of understanding between New Zealand's Department of Conservation (DOC) and China's State Forestry Administration (SFA) was signed at Pukorokoro Miranda, an internationally significant wetland on the northeast of the North Island, where thousands of red knots and bar-tailed godwits have spent the southern summer.

The red knots breed in Siberia, the godwits breed in Alaska, but they both land at wetlands in China, to refuel before flying on to their breeding sites.

DOC and the SFA will work together to protect, manage and restore wetlands where red knots, godwits and other migratory shorebirds stop to feed during annual migrations.

"These small birds that fly non-stop between New Zealand and China form a bridge between our two countries. They connect us as people. We will work together to keep the bridge open,"?said Chen Fengxue, the Chinese minister responsible for the SFA?in a statement.

A key wetland covered by the agreement is a 7-km stretch of coastal mudflat and salt ponds at Luannan on Bohai Bay, where half of the red knots land after flying non-stop from New Zealand.

The red knots refuel on shellfish before flying to their breeding sites in Siberia.

A second wetland covered by the agreement is in the Yalu Jiang Nature Reserve, near Dandong on the Chinese border with the Democratic People's Republic of Korea.

Half the godwits that summer in New Zealand stop over at Yalu Jiang on their way to breeding sites in Alaska.

"The MOA (memorandum of understanding) we've signed shows DOC in New Zealand and the SFA in China are committed to working together to ensure these remarkable birds can continue to make these epic journeys," DOC director-general Lou Sanson said in the statement.

The MOA formalizes a relationship between the Pukorokoro-Miranda Naturalists' Trust and the Yalu Jiang National Nature Reserve that began 17 years ago.

"The only way to protect these birds is to protect their habitat, the number of these birds is declining. Signing the MOA marks a significant step in securing a safe flight path for the red knots, godwits and other migratory birds that fly between New Zealand and China," trust chair Gillian Vaughan said in the statement.