The pair, in their 30s, were arrested at a property on Lyndale Crescent, Heckmondwike, and are suspected of having roles in trafficking heroin from Pakistan, and arranging its onward sale across the UK.
They are believed to be part of an organised crime group linked to a number of substantial seizures of heroin since October 2020 at Heathrow Airport.
A further property in the Heckmondwike area was searched, along with a further two houses in Birstall and Wakefield.
This stunning home is the most expensive for sale in Dewsbury on Rightmove
Met Office issue yellow weather warning for thunder across West Yorkshire
Kirklees gardeners to get discount on composters
Kirklees Council: Does your child qualify for free school meals?
Yorkshire Water announces hosepipe ban
One of the properties is linked to a second man who is wanted in connection to the same conspiracy and is believed to no longer be in the UK.
Officers attending the searches recovered quantities of drugs likely to be cocaine and heroin, as well as drugs paraphernalia and thousands of pounds in cash.
Both the man and the woman remain in custody for further questioning. Searches at the properties are ongoing.
NCA Operations Manager Nigel Coles, said: “The drugs trade fuels violence, ruins lives and can devastate communities.
“These arrests are part of an ongoing investigation and shows the NCA’s commitment to tackling the trade in Class A drugs from source to consumer.”