Primary Industries Minister Nathan Guy says significant changes have been made at the border since the velvetleaf incursion.
The pest plant entered the country in contaminated fodder beet seed and as of last month there had been 244 detections of it in 11 regions.
The government called off its program to destroy it, saying it was unlikely it could be eradicated.
Mr Guy told Parliament's Primary Production Select Committee this morning about the border changes.
"And they are that we've closed down the six lines of fodder beet coming in, there's more rigourous testing, and any coated seed needs to be signed off by a technical officer at the border."