diff --git a/platform/z1/dev/i2cmaster.c b/platform/z1/dev/i2cmaster.c
index c2bad507d..2da89ef7b 100644
--- a/platform/z1/dev/i2cmaster.c
+++ b/platform/z1/dev/i2cmaster.c
@@ -183,6 +183,14 @@ i2c_enable(void) {
   I2C_PxOUT |= (I2C_SDA | I2C_SCL);    // Select pull-up resistors
 }
 
+void
+i2c_disable(void) {
+  I2C_PxSEL &= ~(I2C_SDA | I2C_SCL);    // GPIO function selected
+  I2C_PxSEL2 &= ~(I2C_SDA | I2C_SCL);   // GPIO function selected
+  I2C_PxREN &= ~(I2C_SDA | I2C_SCL);    // Deactivate internal pull-up/-down resistors
+  I2C_PxOUT &= ~(I2C_SDA | I2C_SCL);    // Select pull-up resistors
+}
+
 /*----------------------------------------------------------------------------*/
 //------------------------------------------------------------------------------
 // void i2c_transmit_n(unsigned char byte_ctr, unsigned char *field)
diff --git a/platform/z1/dev/i2cmaster.h b/platform/z1/dev/i2cmaster.h
index 192e99ea1..25bd7c233 100644
--- a/platform/z1/dev/i2cmaster.h
+++ b/platform/z1/dev/i2cmaster.h
@@ -44,6 +44,7 @@
 #include "contiki.h"
 
 void i2c_enable(void);
+void i2c_disable(void);
 
 void i2c_receiveinit(uint8_t slave_address);
 uint8_t i2c_receive_n(uint8_t byte_ctr, uint8_t *rx_buf);