New Zealand Customs officers seized a record 246 million NZ dollars (163.02 million US dollars) worth of methamphetamine at the border in the first half of the year, while authorities in China's Hong Kong stopped another 7.5 million NZ dollars (4.97 million US dollars) worth of the drug reaching New Zealand, customs officials said Wednesday.

In the year to the end of June, New Zealand Customs made 1,660 separate drug seizures, including more than half a tonne of methamphetamine or its precursors.

The crystal methamphetamine was estimated to be worth up to 141 million NZ dollars (93.37 million US dollars) in street value, and the precursors up to 105 million NZ dollars (69.53 million US dollars).

"It's not uncommon for customs to intercept several kilograms of methamphetamine or precursors in each seizure, sometimes on a daily basis. A major shift in precursors over the last 18 months is the import of ephedrine instead of pseudoephedrine," customs manager border operations Shane Panettiere said in a statement.

Customs manager investigations Maurice O'Brien said customs had made numerous arrests relating to drug importation offenses in the first six months of the year.

"Customs is actively working with local and international agencies to target and stop drugs, disrupt and dismantle the international supply chains, and identify and pursue all those involved - wherever they may be," said O'Brien.

"An example of this is that in addition to local border seizures, Hong Kong Customs has also seized about 7.5 kg of methamphetamine destined for New Zealand."

Customs Minister Nicky Wagner said the government would continue to work closely with international agencies to stop drugs before they are exported.

"Thanks to the dedication and skill of our Customs officers as well as the action of law enforcement agencies here and overseas, this significant amount of harmful drugs has been kept off our streets," Wagner said in a statement.